● Output protection of AOD08DP
The output driver of this module is capable of detecting an overcurrent and measuring
its own temperature. When an accident, such as the ground fault of wiring, causes an
abnormal increase in the load current, the current limiter in the driver limits the load
current. Temperature of the driver rises when this overcurrent lasts. Then a protection
circuit makes the output of the driver turn off. After that, the output of the driver repeats
ON and OFF status. If an above accident occurred, the red LED "F" in front of this
module is turned on.
In this module, when the output is turned off by the output protection, the DI identifies
the DO driver which has been detected the alarm. Therefore, assign this module to any
DI address of 1 byte. Bit value of DI corresponding to the DO driver which the alarm is
detected repeats “1” and “0”. The period of time bit value of DI is “1” is more than
10msec. When the output protection is operated, turn off the DO and system power.
Then eliminate the cause of the overload.
Waveform of DO driver output and DI when the output protection is operated is as
7 6 5 4 3 2 1 0
A7 A6 A5 A4 A3 A2 A1 A0
Bit value of DI its bit number is same as DO (A0-A7) which the alarm is
detected is turns to “1”.
FANUC I/O Unit-MODEL
8pt DC output module with short
circuit protection (AOD08DP)
DESCRIPTION DESIG. DATE
More than 10msec
When overcurrent caused by ground fault of wiring or some
other failure lasts for a long time, this module may break
down. Therefore, program the sequence that the DO signal,
corresponding to bit number of DI which bit value is “1” by
alarm detection, is turned off.